The technology to be developed in this study would enable oxygenation of blood by intra-aortic infusion of a highly oxygenated carrier liquid. The liquid would be oxygenated at sufficiently high concentrations (10 - 40 cm3 dissolved gaseous oxygen/gram liquid) that, after infusion, the blood oxygen content would be raised to the levels achieved through the normal respiratory function of the lungs, with a low enough fluid load to allow long-term systemic applications. This approach provides an alternative to the existing paradigm that systemic or regional tissue hypoxia is only correctable by diffusion of oxygen across an interface (lungs/artificial membrane) between gas and the systemic blood volume. In the proposed approach, by using oxygen pre-dissolved in a carrier liquid which is delivered so as to suppress nucleation, oxygenation is accomplished by the more efficient mechanism of liquid-liquid mixing. The approach has applications to treatments of tissue hypoxia which span a wide range of pathophysiologic problems in medicine and surgery. To achieve nucleation-free delivery and mixing of oxygenated solutions at the required oxygen concentration, experimental and theoretical research is needed on the preparation of gas-supersaturated solutions, their delivery along capillary tubes, and their mixing with co-flowing blood at the distal tube-end. Techniques for preparing stable oxygen- supersaturated liquids and nucleation theories, developed by the principal investigators in earlier work to explain suppression of nucleation during transport along micron-size capillary tubeses, will be extended to preparation of oxygenated solutions at much higher concentrations and to understanding thresholds for nucleation during transport along sub-micron capillary tubes. The research needed in these areas is critical to achieving safe oxygenation by liquid-liquid mixing at the desired oxygen levels.